The present invention refers to a filling tube assembly for being mounted to a clipping machine for producing sausage-shaped products, like sausages, by feeding flowable filling material, in a filling process, into a tubular or bag-shaped packaging casing. The filling tube assembly comprises a mounting unit for mounting the filling tube assembly to the clipping machine and a filling tube for feeding flowable filling material in a feeding direction into a tubular or bag-shaped packaging casing. The packaging casing is being consumably arranged on the filling tube. The filling tube has a filling inlet for receiving the filling material, a filling outlet for discharging the filling material into the packaging casing and a filling tube axis, extending between the filling inlet and the filling outlet. The filling tube is pivotable relative to the mounting unit around a pivot axis at least between a production position and an interchanging position. The filling tube assembly further comprises a casing brake unit with a brake axis, a casing brake holder and a casing brake for being reversibly coupled to the casing brake holder. The casing brake holder is configured for reversibly holding the casing brake on the filling tube in a braking position, in which the brake axis is at least basically coaxial with the filling tube axis. The casing brake holder together with the casing brake is moveable between the braking position and a releasing position by a pivoting and translational action. In the releasing position, the casing brake holder together with the casing brake is pivoted away from the filling tube in a way that unfilled packaging casing can be loaded onto the filling tube.
In practice, it is known that, e.g. in the production of sausage-shaped products, like sausages, paste-like, granular and/or liquid material is fed by a filling machine with a filling pressure through a filling tube of a clipping machine in a feeding direction into a tubular or bag-shaped packaging casing. The packaging casing is stored on the filling tube and closed at its front end, e.g. the end pointing in or downstream the feeding direction, by a closure means, like a closure clip. During the filling process, the packaging casing is filled with the filling material and pulled-off the filling tube by the filling pressure. For preventing the tubular or bag-shaped packaging casing from uncontrolled sliding-off the filling tube, a casing brake unit with a casing brake is provided, wherein the casing brake is detachably arranged on the filling tube and kept in position by a casing brake holder. The casing brake is configured for providing a frictional force to the packaging casing, at least while the packaging casing is being pulled-off the filling tube during the filling process, thus controlling the pull-off speed of the packaging casing from the filling tube and ensuring an approximately constant filling degree. After a predetermined volume of filling material has been filled into the packaging casing, a displacer unit forms a plait-like portion to an open end of the just filled packaging casing that is pointing against or upstream the feeding direction. The displacer unit usually comprises a first and a second displacer member which can each be formed by a pair of mutually movable displacement elements for compressing the filled packaging casing, thereby displacing the filling material from the respective area and mutually moving away in or against the feeding direction, hence forming the plait-like portion of the tubular packaging casing. Subsequently, the bag end is being closed by a clipping unit with respective closing tools which are reversibly movable towards the plait-like portion of the clipping machine by placing and closing at least one closure clip at the plait-like portion of the packaging casing, thus forming the rear end of the sausage-shaped product, namely the end pointing against or upstream the feeding direction. As well as the rear end, by these means a new closed front end for a succeeding sausage-shaped product is provided. Optionally, in a final step, the sausage-shaped product that just has been closed at its rear end is cut-off the packaging casing that is provided on the filling tube and has not been filled yet by a cutting unit.
For providing the tubular packaging casing on the filling tube, there are basically two methods available.
According to a first method, an axially compressed batch of packaging casing that has already a tubular shape is provided on the filling tube by being imposed onto the filling tube from its delivery end, e.g. the end of the filling tube facing in the feeding direction of the filling material and having a filling outlet. Therefore, the operator needs an easy access to the filling tube, wherein usually at least the casing brake has to be removed from the filling tube. The advantage of this configuration is that it requires less space and the production speed is only dependent on the speed of the filling, displacement, closing and the optional cutting process. A disadvantage of the second method is that, in case the packaging casing provided on the filling tube is consumed, a new batch of tubular packaging casing has to be loaded onto the filling tube from its delivery end. For this loading process, the casing brake has to be removed from the filling tube for getting access to the open end of the filling tube. In some types of clipping machines, the displacer arrangement, clipping unit and cutting unit are arranged so closely to the delivery end of the filling tube that they have to be removed as well. In other configurations, the filling tube is pivotable relative to the machine base for getting better access to the filling outlet side of the filling tube. This process is usually very time-consuming and requires a great amount of skill and experience of the operator. Consequently, this process will cause unwanted production down-time.
Furthermore, the diameter of the sausage-shaped product to be produced defines the outer diameter of the filling tube and the inner diameter of the casing brake, respectively. Therefore, in order to produce sausage-shaped products of different diameters, different filling tubes with corresponding outer diameters and casing brakes with corresponding inner diameters have to be used. Accordingly, for switching production to sausage-shaped products that have a diameter different from the previously produced sausage-shaped products, at least the previously used filling tube has to be replaced by a suitable filling tube having a compatible diameter to the sausage-shaped products to be produced. In addition, either the previously used casing brake is not compatible with the suitable filling tube and has to be replaced by a suitable casing brake or the previously used casing brake has an adjustable inner diameter that can be fitted to the selected filling tube, respectively.
Moreover, the inner parts of the casing brake, that are in contact with the outer surface of the tubular packaging casing are usually made of comparatively soft material, e.g. rubber and are subject to permanent friction with the packaging casing. Therefore, casing brakes generally suffer stronger wear-out than other components of the clipping machine, e.g. the filling tube, displacer unit or clipping unit. Worn-out casing brakes can lead to machine failure, e.g. by damaging the packaging casing or providing insufficient friction to the packaging casing which will lead to an increased amount of packaging casing being pulled-off the filling tube per product produced. A damaged packaging casing can result in a bursting of the packaging casing during the filling process and thereby spreading the filling material inside and/or outside the clipping machine, thus the clipping machine can be contaminated or even damaged and as a consequence production has to be stopped. Even if the packaging casing does not burst, the product is at least likely to be faulty. Therefore, it is necessary to replace the casing brake of a clipping machine after a certain usage, e.g. time of usage or total length of processed packaging casing.
A second method for providing the tubular packaging casing on the filling tube is used in some types of known clipping machines, wherein the casing brake is provided at the clipping unit of the clipping machine, and wherein the clipping unit and displacer unit are pivotable arranged at the clipping machine. In these known clipping machines, the end of the filling tube that is opposite the filling outlet is pivotably arranged at the clipping machine. Consequently, the filling tube, clipping unit and displacer unit can pivot relatively to the clipping machine around different pivot-axes, wherein clipping unit and displacer unit are usually pivotable around the same pivot-axis. For replacing the filling tube and/or feeding packaging casing to the filling tube, the clipping unit with the displacer unit and casing brake has to be pivoted, thus removing the casing brake from the filling tube. Subsequently, the filling tube can be pivoted away from the clipping machine to a suitable position for replacing the filling tube and/or feeding packaging casing to the filling tube. This procedure is generally complicated and requires several operations to be performed by a skilled operator subsequently.
In another type of known clipping machines, the clipping unit and displacer unit are fixedly attached to the clipping machine. The filling tube is pivotably arranged at the clipping machine. The pivot axis of the filling tube is arranged upstream the filling tube with respect to the feeding direction. The casing brake holder comprises a guide rail for holding the casing brake on the filling tube when the filling tube is not pivoted away from the clipping machine. The guide rail of the casing brake holder is usually shaped like a fork, comprising at least two teeth, wherein the casing brake is interposed in between the two teeth, when the casing brake holder is arranged on the filling tube and the filling tube is not pivoted away from the clipping machine. Consequently, the casing brake holder is configured for releasing the casing brake when the filling tube with the casing brake still mounted is pivoted away from the clipping machine. Once the filling tube is pivoted away from the clipping machine to a degree that the casing brake is moved out of the guide rail of the casing brake holder, the casing brake can be removed from the filling tube in direction of the filling tube axis. This whole process, especially the mounting process of the casing brake onto the filling tube and the engaging process of the casing brake with the casing brake holder while pivoting the filling tube back towards the clipping machine, is very cumbersome as well as time consuming and requires a skilled operator.
One solution for arranging a casing brake at a clipping machine for being removably attached to a filling tube is disclosed in DE utility model 20 2009 013 062. The casing brake holder is attached to a wheeled crab that is guided on an S-shaped rail. The rail is fixedly attached to the clipping machine. The filling tube is pivotably attached to the clipping machine as well. By pivoting the filling tube together with the casing brake away from the clipping machine, the crab is forced along the rail, thereby pulling the casing brake off the filling tube. For reassembling the casing brake back onto the clipping machine after the new tubular packaging casing has been imposed onto the filling tube, the casing brake has to be pushed back onto the filling tube and will be forced back to the braking position by the crab when the filling tube is pivoted back to the production position. This system holds the disadvantage that due to the pivoting action of the filling tube, radial oriented forces are introduced from the filling tube to the casing brake. Moreover, due to the axial movement of the casing brake with respect to the filling tube in combination with the radial oriented forces, the casing brake is subject to increased strain. Consequently, since the casing brake is usually made of relatively soft material, like rubber or silicone, the pivoting procedure can cause damages to the casing brake. Furthermore, especially the process of rearranging the casing brake onto the filling tube is inconvenient because the casing brake and the filling tube have to be aligned manually.